Comparison of carcass and meat characteristics of three rabbit lines selected for litter size or growth rate.

Rabbits from three synthetic lines were compared. Line V and A were selected for litter size at weaning and line R was selected for growth rate between weaning and slaughter time. Forty animals of each line were slaughtered at 9week of age. Comparisons between lines were made using Bayesian statistical techniques. Line R had a higher meat/bone ratio, higher loin percentage and higher ultimate pH of M. Longissimus lumborum (LL) than A and V, but lower dressing out and lower hind part percentages. Some differences between lines in carcass and meat colour were found. No differences were found for percentage of released water of LL and for the activity of energy metabolic enzymes. At present, rabbit carcasses are not costed according to their retail cuts or meat/bone ratio, but dressing out percentage is taken into account, thus breeding companies should be concerned about lower carcass yield of lines selected by growth rate.

Conditioning to ethanol in the fruit fly-a study using an inhibitor of ADH.

To identify processes involved in the choice of ethanol by adult Drosophila, flies homozygous Adh(F), reared in the absence of alcohol were placed in contact with: a) an ethanol-free medium, b) a medium containing ethanol, c) a medium supplemented with 4-methylpyrazole (4-MP, an inhibitor of the ADH pathway), d) a medium containing ethanol and 4-MP. The choice of ethanol over a medium without ethanol was evaluated by measuring the duration of extension of the proboscis of the flies in each of the media. A slight preference for the ethanol-supplemented medium was observed in the naive flies, which was enhanced by previous exposure to ethanol. Exposure to ethanol and 4-MP, however, led to an avoidance of ethanol. There was a reduction in ADH activity on treatment of the flies with 4-MP, and signs of malaise (reduced locomotor activity, loss of balance) were observed in the flies who ingested both ethanol and inhibitor. We concluded that the preference for ethanol stems from an associative learning related to ethanol utilization. Inhibition of enzymes of ADH pathway led to a conditioned aversion due to disturbance of ethanol metabolism giving rise to malaise.

Spontaneous locomotor activity of Drosophila melanogaster flies at various gravity levels (0 g, 1 g, 1.8 g) during parabolic flights.

The spontaneous locomotor activity of young, middle-aged and old Drosophila melanogaster of both sexes has been videorecorded during three parabolic flights separated by one-day intervals. Fast shifts between 0 g, 1 g and 1.8 g phases are obtained during parabolic flights. Results showed that the activity scores were higher at 0 g during the first flight, but that this effect of microgravity was erased during the two next flights. It may be concluded that flies showed a transient form of reactivity to a new environment, i.e. to repeated rapid variations of gravity levels.